ECOLOGY PART II:ECOSYSTEMS & COMMUNITIES

Chapters 24.3, 25.3, 26.1

What Makes Up an Ecosystem?• Biotic Factors: living or once-living environmental

features in an ecosystem.• Abiotic Factors: non-living physical features.

How Do Organisms Interact in an Ecosystem?• Predator/Prey Interactions

• Predator: consumer that captures and eats other consumers

• Prey: organism that is captured and eaten by predator

What is Symbiosis?• Symbiosis: any close relationship between species.

• Mutualism: relationship where both species benefit• Commensalism: one species benefits and one is

unaffected

What is Symbiosis? (cont.)• Parasitism: relationship in which one organism benefits

(the parasite) and the other is harmed (the host)

How do Organisms Produce Food?• Producers: organisms that use an outside energy source

to produce their own food• Energy from the sun is captured by plants, algae, or

bacteria through photosynthesis.• Energy from chemicals is captured by some bacteria

through chemosynthesis.

How do Organisms Consume Food?• Consumers: organisms that obtain energy by eating

other organisms.• Herbivores: eat plants (deer and rabbits)• Carnivores: eat animals (frogs and lions)• Omnivores: eat both plants and animals (pigs and

humans)• Decomposers: eat dead organisms

What is a Food Chain?

• Food Chain: a model of the feeding relationships in an ecosystem.

What is a Food Web?

• A food web shows all the possible feeding relationships among the organisms in a community.

How Does Energy Move Through an Ecosystem? • An energy pyramid shows the amount of energy available at each feeding level in an ecosystem.

What is an Ecological Disturbance?• Disturbances can change ecosystems, communities, and

populations. • Examples: forest fires, floods, human influences

• Permanent changes to an ecosystem leads to ecological succession: normal, gradual changes that occur in the types of species that live in an area.

What are the Types of Succession?• Primary Succession: begins in a place without soil.

• Example: an ecosystem beginning on bare rock

What are the Types of Succession?• Secondary Succession: begins in a place that has soil

and once had living organisms• Example: after fire or removal of buildings

• Pioneer species: the first species in an ecosystem.• Example: lichens

What are Invasive Species?• Nonnative organisms that spread widely in a community

• A lack of limiting factors such as predators, parasites, or competitors enables their population to grow out of control.

• Not all invasive species are harmful.

Did You Know? Although the European honeybee is invasive to North America, it is beneficial because it pollinates our agricultural crops.